In prior art, such reflectors are known. For example, for lighting the reflectors reflect the radiant power from a light source to an object or a surface that is to be illuminated. A number of lamp types are available to do this having various technologies for generating the corresponding radiant power. These are, for example, filament bulbs or halogen lamps, fluorescent lamps or compact fluorescent lamps, metal halogen vapor lamps or sodium vapor lamps, as well as also induction lamps.
The radiation from the lamp bounces off the reflector whose shape is determined the pattern of light emitted by the lamp, i.e. the lamp filaments or the output of the lamp. The spatial vectors, angles of light incidence and reflection, relative to the perpendicular to the reflector surface.
Different lamps have different shapes. There are, for example, very compact filaments in the case of low-voltage halogen lamps, elongated filaments for rod-shaped high voltage halogen lamps, glowing thin glass tubes in fluorescent lamps or glass tube bundles in compact fluorescent lamps and very small cylindrical outputs for the emitters of metal vapor lamps, as well as U-shaped or helical discharge tubes for flash bulbs.
The surface of the reflectors can be mirror finish smooth or have an array of regular or irregular surface structures. Reflectors have different photometric tasks, for example, a distribution of light intensity of small of, for example, 10°, of spot or medium of 30°, or of flood of 60°.
So that the reflectors and the radiant power of the lamps can reflect in such a way that the desired objects are illuminated with the proper light, the reflectors solve several problems.
The reflectors are developed and manufactured in such a way that the desired distribution of the intensity of light can be achieved by the reflector shape. Thus, efficiency is important in that the reflector can absorb a tolerable maximum of radiant power of the lamp. Only a minimum of multiple reflections should be emitted from the lamp to the reflector and back again to the lamp and then toward the outside. For rod-like long lamps this is a problem axially in the round reflector because when the reflector shape in the direction of the rear side reflector axis is not perfect, the degree of effectiveness can be significantly diminished. The radiant power of the lamp reaches the outside only after several reflections in many wrong directions between the reflector and the lamp.
The various lamp types generate nonhomogeneous radiant power with respect to light intensity of light, as well as light color. Illumination must be even with no color spots created on the objects that are to be illuminated. As a rule, the reflector has a surface that has as high a total reflectivity as possible for the degree of effectiveness of the lamp. But a part of the reflection must be diffuse in order to mix the nonhomogeneous radiation of the lamps, irregularities in the reflector and small assembly errors in the lamp position.
The production of round reflectors concerned here starts with blanks in a spin-shaping process. The spinning tool has the reflector shape, that is the reflector surface is on the spinning tool. This is done by means of sand blasting, erosion, form shaping as per photo specifications, by cutting and in the past also by embossing. The spinning process is a very old technology. Only one reflector per spinning machine can be made at a time. The technology has very high labor costs.
An additional technology for the production of reflectors is tension-compression shaping. During deep drawing, a sheet metal blank is fixed in a die and shaped by a drawing punch in one or more steps into a hollow body. For hydro-mechanical deep drawing, the reflector is created as the result of the drawing punch, subject to the influence of the pressure of a pressure medium. In the case of the hydroshaping process, a membrane protects the future reflector from the pressure medium.
After the spinning process, the reflector must be chemically treated. Its surface must be able to reflect the light with as little absorption as possible, and must also be covered with a protective layer against corrosion. In the interest of the reflection with a minimum of absorption, the purest aluminum is also used in plated form. Brightness is created as the result of anodic brightness with the assistance of continuous current in electrochemical systems. The layer of protection against corrosion is created by anodic oxidation. But this oxidation of the reflector surface also has low diffuse reflection and absorption properties. As a result of additives in the electrochemical baths, the oxide layer is usually colored, so that these subsequent chemical treatments of the reflector surface decrease the effectiveness of the lamp by a small amount. Beyond that, the application of electrochemical baths is a difficult and environmentally damaging technology, but in the case of round reflectors that are produced by spinning, it is indispensable.
There are channel or box reflectors. These are cut from strip material, stamped or lasered. These strip materials have a finished surface. The surface structure is rolled into the flat blank. The total reflection and thus the degree of effectiveness of the lamp is significantly better than in the reflectors mentioned above that are made of blanks or precut parts of untreated aluminum.